This invention relates generally to industrial trucks and more particularly to retractable overhead guards for such trucks. Such a guard may be lowered for operation of the truck in areas of low clearance, and further may be manually lowered or raised.
For vehicles such as lift trucks it is desireable to provide an overhead guard to protect the operator from falling objects. This guard must extend above the vehicle a sufficient distance to provide headroom for the operator. However, in areas of low clearance, whether in a storage area or access areas, the presence of a rigid, non-collapsing guard severly limits the usefulness and efficiency of such a vehicle. A retractable guard allows operation of the vehicle in open as well as restricted areas and may provide operator protection in both situations.
Many such guards have been designed for larger industrial trucks. They are generally quite large to cover the entire truck except for the lifting forks and, accordingly, are rather massive and bulky. This size and mass requires extra support legs, hinders the removal of batteries and other routine maintenance operations, and makes manual adjustment, if possible at all, cumbersome and dangerous. Many of these guards may be adjusted only with hydraulic or other mechanical assistance, which drains battery energy and reduces the efficiency of both the machine and operator. Others require complex or exotic linkages to position the guard or maintain it in position. See, for instance, U.S. Pat. Nos. 2,263,981, issued to Dalecke, et al.; 3,827,532, issued to Minick, Jr. et al.; 4,026,597, issued to Miller et al.; and 4,047,750, issued to Samide et al. Still other vehicles may have retractable guards, but when the guard is lowered the truck is rendered inoperable due to restrictions on the operator's movement, positioning, or view. See, for instance, U.S. Pat. Nos. 3,713,688, issued to Monroe; 3,827,532, issued to Minick Jr., et al.; 4,026,597, issued to Miller et al.; and 4,047,750, issued to Samide.